package pers.han.thread;

import java.util.Random;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

/**
 * 读写锁
 * @author mingshan
 *
 */
public class ReadWriteLockTest {
    public static void main(String[] args) {
        final Queue3 q3 = new Queue3();
        for (int i = 0 ;i < 3; i++) {
            new Thread() {
                public void run() {
                    while (true) {
                        q3.get();
                    }
                }
            }.start();

            new Thread() {
                public void run() {
                    while (true) {
                        q3.put(new Random().nextInt(10000));
                    }
                }
            }.start();
        }
    }
}

class Queue3 {
    //共享数据，只能有一个线程能写该数据，但可以有多个线程同时读该数据。
    private Object data = null;
    ReadWriteLock rwl = new ReentrantReadWriteLock();
    public void get() {
        rwl.readLock().lock();
        try {
            System.out.println(Thread.currentThread().getName() + " be ready to read data!");
            Thread.sleep((long)(Math.random()*1000));
            System.out.println(Thread.currentThread().getName() + "have read data :" + data);
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            rwl.readLock().unlock();
        }
    }

    public void put(Object data) {
        rwl.writeLock().lock();
        try {
            System.out.println(Thread.currentThread().getName() + " be ready to write data!");
            Thread.sleep((long)(Math.random()*1000));
            this.data = data;        
            System.out.println(Thread.currentThread().getName() + " have write data: " + data);
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            rwl.writeLock().unlock();
        }
    }
}
